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Influence of prior exercise on muscle [phosphorylcreatine] and deoxygenation kinetics during high-intensity exercise in men.
- Source :
-
Experimental physiology [Exp Physiol] 2008 Apr; Vol. 93 (4), pp. 468-78. Date of Electronic Publication: 2008 Feb 01. - Publication Year :
- 2008
-
Abstract
- (31)Phosphate-magnetic resonance spectroscopy and near infrared spectroscopy (NIRS) were used for the simultaneous assessment of changes in quadriceps muscle metabolism and oxygenation during consecutive bouts of high-intensity exercise. Six male subjects completed two 6 min bouts of single-legged knee-extension exercise at 80% of the peak work rate separated by 6 min of rest while positioned inside the bore of a 1.5 T superconducting magnet. The total haemoglobin and oxyhaemoglobin concentrations in the area of the quadriceps muscle interrogated with NIRS were significantly higher in the baseline period prior to the second compared with the first exercise bout, consistent with an enhanced muscle oxygenation. Intramuscular phosphorylcreatine concentration ([PCr]) dynamics were not different over the fundamental region of the response (time constant for bout 1, 51 +/- 15 s versus bout 2, 52 +/- 17 s). However, the [PCr] dynamics over the entire response were faster in the second bout (mean response time for bout 1, 72 +/- 16 s versus bout 2, 57 +/- 8 s; P < 0.05), as a consequence of a greater fall in [PCr] in the fundamental phase and a reduction in the magnitude of the 'slow component' in [PCr] beyond 3 min of exercise (bout 1, 10 +/- 6% versus bout 2, 5 +/- 3%; P < 0.05). These data suggest that the increased muscle O(2) availability afforded by the performance of a prior bout of high-intensity exercise does not significantly alter the kinetics of [PCr] hydrolysis at the onset of a subsequent bout of high-intensity exercise. The greater fall in [PCr] over the fundamental phase of the response following prior high-intensity exercise indicates that residual fatigue acutely reduces muscle efficiency.
- Subjects :
- Adult
Humans
Hydrogen-Ion Concentration
Hydrolysis
Kinetics
Magnetic Resonance Spectroscopy
Male
Oxygen blood
Oxyhemoglobins metabolism
Spectroscopy, Near-Infrared
Exercise physiology
Muscle Contraction
Muscle Fatigue
Oxygen metabolism
Oxygen Consumption
Phosphocreatine metabolism
Quadriceps Muscle metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0958-0670
- Volume :
- 93
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- Experimental physiology
- Publication Type :
- Academic Journal
- Accession number :
- 18245201
- Full Text :
- https://doi.org/10.1113/expphysiol.2007.041897